This invention relates to chains in general, and more particularly to improvements in link chains of the type adapted to be utilized with advantage for transmission of torque between rotary parts of transmissions or the like. For example, link chains of the type to which the present invention pertains can be employed to transmit torque between driving and driven pulleys or sheaves in continuously variable transmissions (CVT) of the type employed in the power trains (i.e., between the engines or other prime movers and the wheel axles) of motor vehicles.
Link chains of the type to which the present invention pertains comprise composite chain links having packages or stacks of overlapping plate-like components. The components of neighboring links partially overlap and alternate with each other and are articulately connected to one another by coupling units which permit neighboring links to pivot relative to each other. The coupling units comprise pin-shaped elements extending through windows provided in the components of the respective pairs of links. The end faces of the pin-shaped elements engage the conical surfaces of flanges forming part of aforementioned (normally adjustable) pulleys or sheaves over which the link chain is trained, e.g., in the aforementioned continuously variable transmission of the type often employed in the power trains of motor vehicles.
A drawback of many presently known link chains is that they are noisy due to excessive play between neighboring parts such as the plate-like components of the composite links, the pin-shaped elements of the units which couple neighboring links to each other, and/or the flanges of the pulleys at least one of which drives the chain and at least one of which receives torque from the chain when the transmission is in use.
Another drawback of many presently known link chains is that they undergo rapidly progressing pronounced wear in actual use of the chains; this results in the generation of even more pronounced noise which is particularly undesirable when the link chain is employed in the power train of a motor vehicle.
A further drawback of conventional link chains is that their links cannot or are not likely to reassume predetermined starting positions relative to each other as well as that they cannot be readily confined to repeated pivotal movements to predetermined end positions. This can affect the accuracy with which a conventional link chain can transmit torque in a continuously variable transmission or the like.
Still another drawback of presently known link chains is that they are complex, that their useful life is rather short as well as that they are too expensive, especialy if made to stand extensive periods of repeated use such as in the power trains of motor vehicles.